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tegra_pcm.c

/*
 * tegra_pcm.c - Tegra PCM driver
 *
 * Author: Stephen Warren <swarren@nvidia.com>
 * Copyright (C) 2010 - NVIDIA, Inc.
 *
 * Based on code copyright/by:
 *
 * Copyright (c) 2009-2010, NVIDIA Corporation.
 * Scott Peterson <speterson@nvidia.com>
 * Vijay Mali <vmali@nvidia.com>
 *
 * Copyright (C) 2010 Google, Inc.
 * Iliyan Malchev <malchev@google.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include "tegra_pcm.h"

static const struct snd_pcm_hardware tegra_pcm_hardware = {
      .info             = SNDRV_PCM_INFO_MMAP |
                          SNDRV_PCM_INFO_MMAP_VALID |
                          SNDRV_PCM_INFO_PAUSE |
                          SNDRV_PCM_INFO_RESUME |
                          SNDRV_PCM_INFO_INTERLEAVED,
      .formats          = SNDRV_PCM_FMTBIT_S16_LE,
      .channels_min           = 2,
      .channels_max           = 2,
      .period_bytes_min = 1024,
      .period_bytes_max = PAGE_SIZE,
      .periods_min            = 2,
      .periods_max            = 8,
      .buffer_bytes_max = PAGE_SIZE * 8,
      .fifo_size        = 4,
};

static void tegra_pcm_queue_dma(struct tegra_runtime_data *prtd)
{
      struct snd_pcm_substream *substream = prtd->substream;
      struct snd_dma_buffer *buf = &substream->dma_buffer;
      struct tegra_dma_req *dma_req;
      unsigned long addr;

      dma_req = &prtd->dma_req[prtd->dma_req_idx];
      prtd->dma_req_idx = 1 - prtd->dma_req_idx;

      addr = buf->addr + prtd->dma_pos;
      prtd->dma_pos += dma_req->size;
      if (prtd->dma_pos >= prtd->dma_pos_end)
            prtd->dma_pos = 0;

      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
            dma_req->source_addr = addr;
      else
            dma_req->dest_addr = addr;

      tegra_dma_enqueue_req(prtd->dma_chan, dma_req);
}

static void dma_complete_callback(struct tegra_dma_req *req)
{
      struct tegra_runtime_data *prtd = (struct tegra_runtime_data *)req->dev;
      struct snd_pcm_substream *substream = prtd->substream;
      struct snd_pcm_runtime *runtime = substream->runtime;

      spin_lock(&prtd->lock);

      if (!prtd->running) {
            spin_unlock(&prtd->lock);
            return;
      }

      if (++prtd->period_index >= runtime->periods)
            prtd->period_index = 0;

      tegra_pcm_queue_dma(prtd);

      spin_unlock(&prtd->lock);

      snd_pcm_period_elapsed(substream);
}

static void setup_dma_tx_request(struct tegra_dma_req *req,
                              struct tegra_pcm_dma_params * dmap)
{
      req->complete = dma_complete_callback;
      req->to_memory = false;
      req->dest_addr = dmap->addr;
      req->dest_wrap = dmap->wrap;
      req->source_bus_width = 32;
      req->source_wrap = 0;
      req->dest_bus_width = dmap->width;
      req->req_sel = dmap->req_sel;
}

static void setup_dma_rx_request(struct tegra_dma_req *req,
                              struct tegra_pcm_dma_params * dmap)
{
      req->complete = dma_complete_callback;
      req->to_memory = true;
      req->source_addr = dmap->addr;
      req->dest_wrap = 0;
      req->source_bus_width = dmap->width;
      req->source_wrap = dmap->wrap;
      req->dest_bus_width = 32;
      req->req_sel = dmap->req_sel;
}

static int tegra_pcm_open(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct tegra_runtime_data *prtd;
      struct snd_soc_pcm_runtime *rtd = substream->private_data;
      struct tegra_pcm_dma_params * dmap;
      int ret = 0;

      prtd = kzalloc(sizeof(struct tegra_runtime_data), GFP_KERNEL);
      if (prtd == NULL)
            return -ENOMEM;

      runtime->private_data = prtd;
      prtd->substream = substream;

      spin_lock_init(&prtd->lock);

      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            dmap = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
            setup_dma_tx_request(&prtd->dma_req[0], dmap);
            setup_dma_tx_request(&prtd->dma_req[1], dmap);
      } else {
            dmap = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
            setup_dma_rx_request(&prtd->dma_req[0], dmap);
            setup_dma_rx_request(&prtd->dma_req[1], dmap);
      }

      prtd->dma_req[0].dev = prtd;
      prtd->dma_req[1].dev = prtd;

      prtd->dma_chan = tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT);
      if (IS_ERR(prtd->dma_chan)) {
            ret = PTR_ERR(prtd->dma_chan);
            goto err;
      }

      /* Set HW params now that initialization is complete */
      snd_soc_set_runtime_hwparams(substream, &tegra_pcm_hardware);

      /* Ensure that buffer size is a multiple of period size */
      ret = snd_pcm_hw_constraint_integer(runtime,
                                    SNDRV_PCM_HW_PARAM_PERIODS);
      if (ret < 0)
            goto err;

      return 0;

err:
      if (prtd->dma_chan) {
            tegra_dma_free_channel(prtd->dma_chan);
      }

      kfree(prtd);

      return ret;
}

static int tegra_pcm_close(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct tegra_runtime_data *prtd = runtime->private_data;

      tegra_dma_free_channel(prtd->dma_chan);

      kfree(prtd);

      return 0;
}

static int tegra_pcm_hw_params(struct snd_pcm_substream *substream,
                        struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct tegra_runtime_data *prtd = runtime->private_data;

      snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

      prtd->dma_req[0].size = params_period_bytes(params);
      prtd->dma_req[1].size = prtd->dma_req[0].size;

      return 0;
}

static int tegra_pcm_hw_free(struct snd_pcm_substream *substream)
{
      snd_pcm_set_runtime_buffer(substream, NULL);

      return 0;
}

static int tegra_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct tegra_runtime_data *prtd = runtime->private_data;
      unsigned long flags;

      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
            prtd->dma_pos = 0;
            prtd->dma_pos_end = frames_to_bytes(runtime, runtime->periods * runtime->period_size);
            prtd->period_index = 0;
            prtd->dma_req_idx = 0;
            /* Fall-through */
      case SNDRV_PCM_TRIGGER_RESUME:
      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            spin_lock_irqsave(&prtd->lock, flags);
            prtd->running = 1;
            spin_unlock_irqrestore(&prtd->lock, flags);
            tegra_pcm_queue_dma(prtd);
            tegra_pcm_queue_dma(prtd);
            break;
      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
      case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
            spin_lock_irqsave(&prtd->lock, flags);
            prtd->running = 0;
            spin_unlock_irqrestore(&prtd->lock, flags);
            tegra_dma_dequeue_req(prtd->dma_chan, &prtd->dma_req[0]);
            tegra_dma_dequeue_req(prtd->dma_chan, &prtd->dma_req[1]);
            break;
      default:
            return -EINVAL;
      }

      return 0;
}

static snd_pcm_uframes_t tegra_pcm_pointer(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct tegra_runtime_data *prtd = runtime->private_data;

      return prtd->period_index * runtime->period_size;
}


static int tegra_pcm_mmap(struct snd_pcm_substream *substream,
                        struct vm_area_struct *vma)
{
      struct snd_pcm_runtime *runtime = substream->runtime;

      return dma_mmap_writecombine(substream->pcm->card->dev, vma,
                              runtime->dma_area,
                              runtime->dma_addr,
                              runtime->dma_bytes);
}

static struct snd_pcm_ops tegra_pcm_ops = {
      .open       = tegra_pcm_open,
      .close            = tegra_pcm_close,
      .ioctl            = snd_pcm_lib_ioctl,
      .hw_params  = tegra_pcm_hw_params,
      .hw_free    = tegra_pcm_hw_free,
      .trigger    = tegra_pcm_trigger,
      .pointer    = tegra_pcm_pointer,
      .mmap       = tegra_pcm_mmap,
};

static int tegra_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
{
      struct snd_pcm_substream *substream = pcm->streams[stream].substream;
      struct snd_dma_buffer *buf = &substream->dma_buffer;
      size_t size = tegra_pcm_hardware.buffer_bytes_max;

      buf->area = dma_alloc_writecombine(pcm->card->dev, size,
                                    &buf->addr, GFP_KERNEL);
      if (!buf->area)
            return -ENOMEM;

      buf->dev.type = SNDRV_DMA_TYPE_DEV;
      buf->dev.dev = pcm->card->dev;
      buf->private_data = NULL;
      buf->bytes = size;

      return 0;
}

static void tegra_pcm_deallocate_dma_buffer(struct snd_pcm *pcm, int stream)
{
      struct snd_pcm_substream *substream = pcm->streams[stream].substream;
      struct snd_dma_buffer *buf = &substream->dma_buffer;

      if (!buf->area)
            return;

      dma_free_writecombine(pcm->card->dev, buf->bytes,
                        buf->area, buf->addr);
      buf->area = NULL;
}

static u64 tegra_dma_mask = DMA_BIT_MASK(32);

static int tegra_pcm_new(struct snd_card *card,
                        struct snd_soc_dai *dai, struct snd_pcm *pcm)
{
      int ret = 0;

      if (!card->dev->dma_mask)
            card->dev->dma_mask = &tegra_dma_mask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = 0xffffffff;

      if (dai->driver->playback.channels_min) {
            ret = tegra_pcm_preallocate_dma_buffer(pcm,
                                    SNDRV_PCM_STREAM_PLAYBACK);
            if (ret)
                  goto err;
      }

      if (dai->driver->capture.channels_min) {
            ret = tegra_pcm_preallocate_dma_buffer(pcm,
                                    SNDRV_PCM_STREAM_CAPTURE);
            if (ret)
                  goto err_free_play;
      }

      return 0;

err_free_play:
      tegra_pcm_deallocate_dma_buffer(pcm, SNDRV_PCM_STREAM_PLAYBACK);
err:
      return ret;
}

static void tegra_pcm_free(struct snd_pcm *pcm)
{
      tegra_pcm_deallocate_dma_buffer(pcm, SNDRV_PCM_STREAM_CAPTURE);
      tegra_pcm_deallocate_dma_buffer(pcm, SNDRV_PCM_STREAM_PLAYBACK);
}

struct snd_soc_platform_driver tegra_pcm_platform = {
      .ops        = &tegra_pcm_ops,
      .pcm_new    = tegra_pcm_new,
      .pcm_free   = tegra_pcm_free,
};

static int __devinit tegra_pcm_platform_probe(struct platform_device *pdev)
{
      return snd_soc_register_platform(&pdev->dev, &tegra_pcm_platform);
}

static int __devexit tegra_pcm_platform_remove(struct platform_device *pdev)
{
      snd_soc_unregister_platform(&pdev->dev);
      return 0;
}

static struct platform_driver tegra_pcm_driver = {
      .driver = {
            .name = "tegra-pcm-audio",
            .owner = THIS_MODULE,
      },
      .probe = tegra_pcm_platform_probe,
      .remove = __devexit_p(tegra_pcm_platform_remove),
};

static int __init snd_tegra_pcm_init(void)
{
      return platform_driver_register(&tegra_pcm_driver);
}
module_init(snd_tegra_pcm_init);

static void __exit snd_tegra_pcm_exit(void)
{
      platform_driver_unregister(&tegra_pcm_driver);
}
module_exit(snd_tegra_pcm_exit);

MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
MODULE_DESCRIPTION("Tegra PCM ASoC driver");
MODULE_LICENSE("GPL");

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